Specialized lighting fixtures, for commercial and theatrical lighting, for example, frequently utilize various forms of accessories, such as filters, conditioners and lenses to modify the shape, color or other aspects of the emitted lighting. These accessories may be changed from time to time to achieve different lighting effects, and a number of arrangements have been proposed heretofore to accommodate such periodic changes. The fixture of the Kane et al U.S. Pat. No. 6,942,368, for example, utilizes a removable cartridge in which accessory elements are installed in advance of the cartridge itself being placed in the fixture. One of its important advantages is that the accessory group may be pre-assembled at ground level, which facilitates and makes safer the final installation, which frequently must take place on a high ladder. Many other proposals can, however, be overly complicated and expensive and/or can be more cumbersome and time consuming than is desired.